Detail:

Abstract:
　　In recent years, two-dimensional (2D) or quasi-2D materials have attracted numerous interests for their fascinating properties. It is highly desirable to design new functional 2D materials. A method based on the particle swarm optimization (PSO) algorithm is proposed to design 2D and Q2D materials. With this development, we discover several new functional 2D/Q2D materials: a new 2D semiconducting material C3N, which was recently confirmed experimentally; two hydrogenated materials of layered Si8H2 and Si6H2 possessing quasi-direct band gaps of 0.75 eV and 1.59 eV, respectively, which have potential for the applications in light emitting diode and photovoltaics devices; a new three-layer Q2D Bi4F4 structure, which is a 2D topological insulator with a large band gap (0.69 eV); 2D P4O4 and 2D P2O3 as good candidates for photochemical water splitting and a novel nanoscale multiple-state memory applications, respectively; 2D hexgonal CrN and CrB2 as 2D hyperferroelectric metals.